Combination triathlon aero handlebar and stem assemblies (referred to herein as “handlebar assemblies”) are known and typically comprise a unitary main body, often advantageously fabricated from a carbon fiber composite, and including a stem portion, right and left airfoil portions extending outwardly of the stem and left and right handle portions situated at the ends of the respective airfoil portions. A pair of relatively closely spaced tubular extensions extends forwardly from the body on either side of the stem portion. The extensions are mounted to the body by way of an extension mount assembly that includes a circular clamp to secure the extensions in place. The extension mount assembly also typically includes elongated fasteners and vertical extension spacers through which the entire assembly is secured to the body with the circular clamp located a desired distance above the body. On top of the extension mount assembly, an elbow rest platform is provided that is typically secured to the extension mount assembly through fasteners. Resilient cushioned pads may be provided to rest on the top of the elbow platform.
The stem portion mounts to a portion of an associated bicycle's fork steerer tube that extends upwardly from the frame of the bike to which it is rotatably secured. Airfoil Stem height spacers are used between a bicycle head tube and the bottom of the stem portion to set the height of the rest of the handlebar assembly. These spacers may have a round cross-section or an airfoil-shaped cross-section.
Traditionally, triathlon handlebar assemblies are designed to both be as aerodynamic as possible as well as facilitate a rider of the associated bicycle to don the most aerodynamic position as is possible while riding. Maximizing aerodynamic efficiency involves (1) minimizing frontal area, and (2) streamlining to reduce drag inducing air flow. To do this the vertical extension spacers, the stem height spacers and the airfoil portions of the body are given streamlined aerodynamic shapes. Further, means are provided for internally routing wires and cables associated with shifters and brake levers that are usually secured to the handlebar assembly. By internally routing the wires and cables, their effect on airflow is eliminated.
In prior art assemblies, it is known to route the wires inside of the extension spacers, which are typically at least partially hollow. This achieves a similar result concerning aerodynamics but makes adjusting the height of the extension spacer stack more difficult and time consuming. Specifically, to add or remove spacers to raise or lower the extension bars, the shifter wires have to be unthreaded to allow a spacer to be removed or to thread the wire through a new spacer that is being added. This can be frustrating especially if the user has to unthread and thread the wires multiple times until he or she settles on the proper extension bar height.
Other prior art assemblies route the shifter wires external to the extension spacers, but either allow the wires to be exposed to the wind, or may attempt to hide them via additional pieces that are secured to the assembly via additional fasteners. These additional pieces present the same problem as above, which is that any adjustment is made unnecessarily difficult by the need to deal with additional parts.
Because of the aerodynamic design, and as indicated above, the stem spacers are aerodynamically shaped, which means they extend forwardly often a couple of inches beyond the front edge of the steerer tube. Because the cable and housing for the front brake is typically fed through the stem portion, the cable must pass through an interior bore of the spacers exiting from the bottommost spacer as it continues its path to the front brake caliper. Using prior art spacers in prior art handlebar assemblies the rider must unthread the brake cable from the caliper and from the spacers' bores before removing or adding spacers to adjust the stem height. If the rider desires to ride the bicycle after each height change to ascertain to his or her satisfaction that the optimal height has been achieved he or she must unthread the cable prior to each change and then rethread the cable before each test ride. This increases the time in making an adjustment and can prove frustrating especially since the brake calipers and the spacing of its shoes from the rim may need to be adjusted each time.
Electronic shifting systems like Di2 by Shimano include control boxes or junction boxes in which the wires from the derailleurs, the battery pack and the shifters meet and communicate. Typically, the control box is attached to the bottom side of a stem. As can be appreciated, mounting the box in this position potentially increases frontal area and as a result aerodynamic drag. Furthermore, the under the stem attachment means is often clunky and unrefined.